Slavery dates back to prehistoric times and was apparently modeled on the domestication of animals. From the earliest periods of recorded history, slavery was found in the world's most "advanced" regions. The earliest civilizations--along the Tigris and Euphrates rivers in Mesopotamia, the Nile in Egypt, the Indus Valley of India, and China's Yangtze River Valley--had slavery. The earliest known system of laws, the Hammurabi Code, recognized slavery. But the percentage of slaves in these early civilizations was small, in part because male war captives were typically killed, while women were enslaved as field laborers or concubines.

Only a handful of societies made slavery the dominant labor force. The first true slave society in history emerged in ancient Greece between the 6th and 4th centuries. In Athens during the classical period, a third to a half of the population consisted of slaves. Rome would become even more dependent on slavery. It is not an accident that our modern ideas of freedom and democracy emerged in a slave society. Most early societies lacked a word for freedom; but large-scale slavery in classical Greece and Rome made these people more aware of the distinctive nature of freedom.
Slavery never disappeared from medieval Europe. While slavery declined in northwestern Europe, it persisted in Sicily, southern Italy, Russia, southern France, Spain, and North Africa. Most of these slaves were "white," coming from areas in Eastern Europe or near the Black Sea.

When Europeans began to colonize the New World at the end of the 15th century, they were well aware of the institution of slavery. As early as 1300, Europeans were using black and Russian slaves to raise sugar on Italian plantations. During the 1400s, decades before Columbus's "discovery" of the New World, Europeans exploited African labor on slave plantations built on sugar producing islands off the coast of West Africa.